Abstract: A method for reciprocal-mixing noise cancellation may include receiving, from a first mixer, a first signal comprising a wanted signal at a first frequency and a modulated signal at a second frequency. The modulated signal may be a product of a reciprocal-mixing of an unwanted signal with a phase noise. The second frequency may be greater than the first frequency, and at least a portion of the modulated signal may overlap the wanted signal, adding a reciprocal-mixing noise to the wanted signal. Using the first signal, a narrow second signal may be generated at a third frequency, twice the second frequency. At a second mixer, the second signal may be mixed with the first signal to generate a third signal. The third signal may be subtracted from the first signal to remove a reciprocal-mixing noise and to generate the wanted signal at the first frequency without the reciprocal-mixing noise.

Abstract: A system for cancellation of a reciprocal-mixing noise may comprise a down-converter mixer that may be configured to down convert a radio-frequency (RF) signal and to generate a baseband signal. The RF signal may include a desired signal and a blocker signal. A first signal path may be configured to receive the baseband signal and to generate a first signal. A second signal path may be configured to receive the baseband signal and to generate a second signal. A subtraction module may be configured to subtract the second signal from the first signal and to generate an output signal. The second signal may comprise the reciprocal-mixing noise, and the output signal may comprise the desired signal substantially free from the reciprocal-mixing noise.

Abstract: A gain control system may include an input terminal that receives an input signal. The gain control system may include a first transistor having a source connected with the input terminal and a drain connected with an output terminal. The gain control system may include a second transistor having a gate connected with the input terminal and the source of the first transistor. The second transistor may have a drain connected with the output terminal. The second transistor may generate a reduction signal. The output terminal may output an output signal based on the input signal and the reduction signal.

Abstract: Aspects of a method and system for a low-noise, highly-linear receiver front-end are provided. In this regard, a received signal may be processed via one or more transconductances, one or more transimpedance amplifiers (TIAs), and one or more mixers to generate a first baseband signal corresponding to a voltage at a node of the receiver, and a second baseband signal corresponding to a current at the node of the receiver. The first signal and the second signal may be processed to recover information from the received signal. The first signal may be generated via a first one or more signal paths of the receiver and the second signal may be generated via a second one or more signal paths of the receiver.

Abstract: A method and apparatus is disclosed to effectively frequency translate a filter characterized as a low quality factor (Q) filter, corresponding to a baseband frequency of approximately zero Hertz or to an intermediate frequency (IF), to a filter characterized as a high Q filter at frequencies greater than the baseband frequency or the IF. A downconversion mixer frequency translates a communication signal to the baseband frequency or the IF using a first local oscillator signal to provide a downconverted communication signal. A filter corresponding to the baseband frequency or the IF filters the downconverted communication signal to provide a filtered communication signal. An upconversion mixer frequency translates a communication signal using a second local oscillator signal. The frequency translation by the upconversion mixer, in effect, translates the filter characterization from the low Q filter to the high Q filter at frequencies greater than the baseband frequency or the IF.

Abstract: A radio front end includes a power amplifier, a tone injection module, a duplexer, a balancing network, and a processor. The tone injection module is operable, in a first mode, to produce a tone having a carrier frequency that is substantially similar to a carrier frequency of an inbound wireless signal. The duplexer is operable, in the first mode, to provide electrical isolation between the outbound wireless signal and a combination signal of the tone and inbound wireless signal and is operable, in a second mode, to provide electrical isolation between the outbound wireless signal and the inbound wireless signal. The processor is operable to determine an amplitude of a tone component of the combination signal; correlate the amplitude of the tone component to an inbound frequency band isolation; and adjust baseband processing of a down converted representation of the combination signal based on the inbound frequency band isolation.

Abstract: A technique to remove second order and third order nonlinearity distortions caused by a blocker signal at an input of a radio receiver. An envelope detector is utilized at an input of the RF front-end of the receiver to obtain a magnitude of the overall signal. The output of the envelope detector is then processed at baseband to estimate coefficients that relate to the distortion. Once the coefficients are obtained, the coefficients are applied at an I/Q imbalance correction stage to also correct for the distortion by cancelling the distortion from the received signal.

Abstract: A radio front module includes a power amplifier, a duplexer, and a tunable balancing network. The power amplifier is operably coupled to amplify an up-converted signal into an outbound wireless signal. The duplexer is operably coupled to an antenna and operable to provide electrical isolation between the outbound wireless signal and an inbound wireless signal. The tunable balancing network is operable to establish an impedance that substantially matches an impedance of the antenna. The tunable balancing network includes a plurality of capacitive elements, a plurality of resistive elements, and a plurality of low-voltage switching elements operable to, and in accordance with a tuning signal, couple one or more of the plurality of capacitive elements and one or more of the plurality of resistive elements to the duplexer as an impedance balancing load.

Abstract: An adaptive cancellation circuit and method are provided. The circuit includes a main path and an auxiliary path. The main path includes a first amplifier configured to output a first amplified signal to a first mixer. The main path is configured to output a first signal comprising a wanted signal component and a distortion component. The auxiliary path includes a second amplifier configured to output a second amplified signal to a second mixer. The second mixer is connected to a filter configured to remove the wanted signal component. The auxiliary path is configured to output a second signal including the distortion component.

Abstract: An RF front-end with on-chip transmitter/receiver isolation using a gyrator is presented herein. The RF front end is configured to support full-duplex communication and includes a gyrator and a transformer. The gyrator includes two transistors that are configured to isolate the input of a low-noise amplifier (LNA) from the output of a power amplifier (PA). The gyrator is further configured to isolate the output of the PA from the input of the LNA. The gyrator is at least partially or fully capable of being integrated on silicon-based substrate.

Abstract: A radio front end includes a power amplifier, a tone injection module, a duplexer, a balancing network, and a processing module. The tone injection module is operable, in a first mode, to produce a tone having a carrier frequency that is substantially similar to a carrier frequency of an inbound wireless signal. The duplexer is operable, in the first mode, to provide electrical isolation between the outbound wireless signal and a combination signal of the tone and inbound wireless signal and is operable, in a second mode, to provide electrical isolation between the outbound wireless signal and the inbound wireless signal. The processing module is operable to determine an amplitude of a tone component of the combination signal; correlate the amplitude of the tone component to an inbound frequency band isolation; and adjust baseband processing of a down converted representation of the combination signal based on the inbound frequency band isolation.

Abstract: A SAW-less transmitter includes an up-conversion mixing module, a frequency translated BPF (FTBPF), an output module, and a power amplifier driver. The up-conversion mixing module converts an outbound symbol stream into an up-converted signal. The FTBPF frequency translates a baseband filter response to an RF bandpass filter response and filter the up-converted signal in accordance with the RF bandpass filter response to produce a filtered up-converted signal. The output module conditions the filtered up-converted signal to produce a conditioned up-converted signal. The power amplifier driver amplifies the conditioned up-converted signal to produce an outbound RF signal.

Abstract: A circuit includes a local oscillator of a transmitter, the local oscillator to generate a transmitter local oscillator signal. A switch controlled by the transmitter local oscillator signal connects with a baseband impedance element to generate a notch frequency signal. The notch frequency signal is added to a transmitter leakage signal to attenuate the transmitter leakage signal prior to demodulation of a desired receiver signal by a receiver.

Abstract: According to one embodiment, a compact low-power receiver comprises a front-end producing a front-end gain and a back-end producing a back-end gain. The front-end includes a transconductance amplifier providing digital gain control and outputting an amplified receive signal, a mixer for generating a down-converted signal from the amplified receive signal, and a transimpedance amplifier (TIA) including a current mode buffer. The TIA provides gain control for amplifying the down-converted signal to produce a front-end output signal. In one embodiment, the back end includes a second-order low-pass filter to produce a filtered signal from the front-end output signal and an analog-to-digital converter (ADC), wherein the filtered signal is fed directly to the ADC without direct-current (DC) offset cancellation being performed. In various embodiments, the front-end gain is substantially greater than the back-end gain.

Abstract: According to one embodiment, a compact low-power receiver comprises first and second analog circuits connected by a digitally controlled interface circuit. The first analog circuit has a first direct-current (DC) offset and a first common mode voltage at an s output, and the second analog circuit has a second DC offset and a second common mode voltage at an input. The digitally controlled interface circuit connects the output to the input, and is configured to match the first and second DC offsets and to match the first and second common mode voltages. In one embodiment, the first analog circuit is a variable gain control transimpedance amplifier (TTA) implemented using a current mode to buffer, the second analog circuit is a second-order adjustable low-pass filter, whereby a three-pole adjustable low-pass filter in the compact low-power receiver is effectively produced.

Abstract: According to one embodiment, a compact low-power receiver comprises first and second analog circuits connected by a digitally controlled interface circuit. The first analog circuit has a first direct-current (DC) offset and a first common mode voltage at an output, and the second analog circuit has a second DC offset and a second common mode voltage at an input. The digitally controlled interface circuit connects the output to the input, and is configured to match the first and second DC offsets and to match the first and second common mode voltages. In one embodiment, the first analog circuit is a variable gain control transimpedance amplifier (TIA) implemented using a current mode buffer, the second analog circuit is a second-order adjustable low-pass filter, whereby a three-pole adjustable low-pass filter in the compact low-power receiver is effectively produced.

Abstract: A gain control system may include an input terminal that receives an input signal. The gain control system may include a first transistor having a source connected with the input terminal and a drain connected with an output terminal. The gain control system may include a second transistor having a gate connected with the input terminal and the source of the first transistor. The second transistor may have a drain connected with the output terminal. The second transistor may generate a reduction signal. The output terminal may output an output signal based on the input signal and the reduction signal.

Abstract: A duplexing system may be used with an electronic device. The duplexing system may include a duplexer connected with an antenna. The duplexing system may include a balancing network. The balancing network may be connected with the duplexer, have an adjustable network impedance, and include an active component. The balancing network may be configured to adjust the network impedance to match an antenna impedance of the antenna.

Abstract: A power distributing duplexer system is provided. In some aspects, the system includes a duplexer configured to couple an antenna to a transmitter and a receiver. The system also includes a balancing network coupled to the duplexer. The balancing network includes a network impedance. The balancing network is configured to adjust the network impedance to match an antenna impedance of the antenna. The balancing network includes a plurality of balancing network modules coupled to the duplexer. Each of the plurality of balancing network modules is configured to receive a portion of an output voltage from the duplexer.

Abstract: An RF front-end with on-chip transmitter/receiver isolation using a gyrator is presented herein. The RF front end is configured to support full-duplex communication and includes a gyrator and a transformer. The gyrator includes two transistors that are configured to isolate the input of a low-noise amplifier (LNA) from the output of a power amplifier (PA). The gyrator is further configured to isolate the output of the PA from the input of the LNA. The gyrator is at least partially or fully capable of being integrated on silicon-based substrate.